Dispersed pigments

ABSTRACT

Disclosed herein are pigment dispersions and inks formulated using the same; including at least one dispersed pigment, an aqueous carrier; and at least one block copolymer dispersant having Structure I and comprising a hydrophobic block (A) and a hydrophilic block (B); at least one block copolymer having Structure I and comprising a hydrophobic block (A) and a hydrophilic block (B);

FIELD OF THE INVENTION

The present invention generally relates to ink-jet printing, and inparticular, to inkjet inks and ink sets using dispersed pigments.

BACKGROUND OF THE INVENTION

The use of digital image-forming apparatuses such as, for example,thermal ink-jet printers, large-format plotters, piezo-electricprinters, laser printers, silver halide grade photo imaging apparatuses,and others has grown in recent years. The growth may be attributed tosubstantial improvements in print resolution and overall print qualitycoupled with appreciable reduction in cost, and ease of use. Today'simage-forming apparatuses offer acceptable print quality for manycommercial, business and household applications at costs lower thanthose offered in the past.

Print media such as those used in off-set printing are smooth and glossydue to a nonporous coating on the surface of the media. The nonporouscoating is a hydrophobic material, such as a hydrophobic polymer. Sincethis coating is hydrophobic, inks used in these types of commercialprinting are typically oil-based. In contrast, the majority of inks usedin inkjet printing are aqueous-based. These inkjet inks are generallynot compatible with the existing non-inkjet commercial print mediabecause the aqueous-based inkjet inks do not penetrate into thenonporous coating, in particular in the fast throughput environment.Therefore, in order to print commercial volumes using inkjet printing,modified inkjet inks for use on non-inkjet compatible commercial printmedia have been developed. However, images printed with these inkjetinks may have reduced resolution, durability, or print quality.

Due to the cost, higher lead time requirements, and efficiencylimitations of these other non-inkjet printing techniques, commercialprinting (including digital printing) using inkjet printers (“commercialinkjet”) is a rapidly developing area. The large volumes of items thatare printed in commercial inkjet printing require high speed printingprocesses. Reliable printer pens that do not need frequent servicing arealso necessary because they contribute to the overall speed of theprinting process.

It would be desirable to provide printing inks for use in ink jetprinters with improved print quality and reliability performance, inparticular for use in commercial inkjet printing as well as personalprinting for home use.

SUMMARY

The present invention is directed to printing liquids and polymericdispersants for formulating the same.

The pigment dispersions and inks formulated using the same, include atleast one dispersed pigment, an aqueous carrier; and at least one blockcopolymer dispersant having Structure I and comprising a hydrophobicblock (A) and a hydrophilic block (B); at least one block copolymerhaving Structure I and comprising a hydrophobic block (A) and ahydrophilic block (B);

Wherein

-   -   C is

-   -   D is

-   -   E is

-   -   F is

-   -   G is

-   -   x1-x2 and y1-y5 are independently selected to be equal to or        greater than zero (0);    -   R1 is H or CH3;    -   R2 is alkyl, or aryl group wherein the number of carbon atoms        ranges from 0 to about 20; including benzyl, butyl, or ester        groups;    -   R3 is H, an alkyl group of from 1 to about 15 carbon atoms, an        aryl group of from about 6 to about 18 carbon atoms; including        arylalkyl, polydimethylsiloxane, polyethylene glycol chain, or a        polypropylene glycol chain.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention is directed to structured copolymers asdispersants, hereinafter interchangeably referred to as resins, forstabilizing pigments for use in printing liquids such as inks includinginkjet inks. Hereinafter the term ink will be used to further describethe invention but its usage is not intended to limit the scope of theinvention. In an embodiment the liquid is usable in inkjet printing(e.g. either or both piezoelectric and thermal inkjet apparatus) usingcommercially available inkjet printers such as the DESKJET®, DESIGNJET®,and PHOTOSMART® families of printers; manufactured by Hewlett-PackardCompany of Delaware.

The inks of the present invention provide printed images having a highprint quality at high throughput rates and enhanced reliabilityperformance by reducing the desorbtion of the resin from the pigment.

Pigmented inks contain solid pigment particles intended normally toimpart color to the ink and are generally dispersed in an aqueous medium(e.g. vehicle). The particles have a natural tendency to settle in thevehicle, thus, resulting in the instability of the ink. In an inkjetink, this settling may lead to color variations of the ink and the imageresulting from the deposition of the ink onto a print medium (e.g.,gloss and color vividness), as well as dysfunction of the printhead.Pigment stability and ink shelf life are important factors in theperformance of the inkjet ink and typically result in challenge in thedesign of the ink.

Pigments are typically stabilized by the adsorption of polymericdispersants onto the pigment surface. The adsorbed dispersant provideselectric double layer and steric layer to the particle surfaces toprevent or minimize coagulation of the pigment in the vehicle. However,most commercial dispersants are made of random copolymers. They cannotprovide for efficient and/or stable bonding to the pigment particles dueto the lack of separation between the hydrophobic and hydrophilic groupswithin the dispersant. Desorption may then occur as solvent andsurfactant are added to further formulate the ink. However, it was foundby the present inventors that increased hydrophobic groups with higherTg (glass transition temperature) may restrain or minimize the onset ofsuch effects.

The resins embodying features of the invention generally include high Tghydrophobic groups. Without intending to limit the scope of the presentinvention, its is believed that the incorporation of the high Tghydrophobic groups in the resins embodying features of the inventionminimize and/or reduce the desorbtion of the resin from the pigment,thus enhancing the stability of the dispersant-pigment system in theink. In an embodiment, monomers are further incorporated in the ink toimprove the dispersant-pigment interaction. The inks of the presentinvention are particularly useful for imaging and photo printers,including commercial inkjet printers. The inks of the present inventionare useful for printing on porous, non-porous, and hybrid glossy mediaand semi-glossy media, as well as micro-porous media for use incommercial inkjet printing applications such as graphic arts and photoretail requiring high throughput and high image quality as well as homephoto printers. Exemplary print media include, but are not limited to,Hewlett-Packard Advanced glossy Photo Paper, Iford Galerie Pearl PhotoInkjet Paper (semi-gloss), Epson Premium Glossy Photo Paper, andPictorico Photo Gallery glossy paper.

In an embodiment, the printing liquid is an ink including a colorantdispersed with a dispersant according to the present invention in avehicle to formulate the ink.

As used herein, the term “printed substrate” means a substrate that isat least partially covered with at least one ink embodying features ofthe invention. “Inkjet pen” means an inkjet pen which has either or bothon-axis and off-axis configurations, including and/or configured toinclude the ink. “Printing system” means a system for printing and/orincluding at least one or more of the inkjet inks embodying one or morefeatures of the present invention, inkjet pen, and/or printer.

Dispersed pigments and inks made according to the present inventionprovide many advantages such as enhanced pigment stability and imagegloss, enabling the use of a broad range of pigments, lower viscositydispersion improving reliability and allowing high pigment loadings forexcellent color performance in low drop volume printheads usable forgenerating higher resolution images.

Polymers

The polymers according to the present invention may generally beclassified into three groups, as described further below:

I. Random, Unstructured Polymers:

Random unstructured polymers may be used, made according to methodsknown to those skilled in the art, including in addition all acrylatesystems and adhesion promoting monomers to further enhance and improvethe pigment-dispersant interaction, thus stability.

II. Structured Polymers:

Structured polymers may be used having a block nature wherein thepolymer is segmented, with the segments having substantial compositiondifference between the various segments.

The block polymers may be designed to include at least two blocks,namely A and B blocks. The A block provides maximum hydrophobicattraction between the dispersant and the pigment surface. The B blockmaximizes the electrostatic stabilization for particle stability. In anembodiment, the hydrophobic block A has a glass transition temperatureranging generally from about 65 to about 140 degrees Celsius (° C.),normally from about 70 to about 120° C.

III. Graft Polymers:

Random polymers with macromonomer side chains grafted onto a backbonemay be used in the practice of the invention. The side chains may beeither or both PEG-acrylate macromonomers and those with terminal alkene(i.e., olefin) group.

The graft polymers may be designed to include a substantiallyhydrophobic backbone providing maximum hydrophobic attraction betweenthe dispersant and the pigment surface; and hydrophilic macromonomerside chains to maximize the electrostatic stabilization for particlestability.

Copolymer Designs

The copolymers embodying features of the present invention may generallyinclude any one or more of structures I-VII below:

Wherein

-   -   C is

-   -   D is

-   -   E is

-   -   F is

-   -   G is

-   -   x1-x2 and y1-y5 are independently selected to be equal to or        greater than zero (0);    -   R1 is H or CH3;    -   R2 is alkyl, or aryl group wherein the number of carbon atoms        ranges from 0 to about 20; including benzyl, butyl, or ester        groups;    -   R3 is H, an alkyl group of from 1 to about 15 carbon atoms, an        aryl group of from about 6 to about 18 carbon atoms; including        arylalkyl, polydimethylsiloxane, polyethylene glycol chain, or a        polypropylene glycol chain.

Structure I, may further be described as Structures II-V

Polymers according to structure II represent an embodiment of polymersaccording to the present invention. Structure II may be modified, asfurther described below, and represented by Structures III and IV belowby adding or removing components.

Structure II, as can be seen includes, at least, components C, D, E, F.In addition it includes R1 and R2 groups, as for example described inreference to Structure I.

The copolymers having structure III include at least two blocks having Aand B groups. The A block provides for tight encapsulation of thepolymer to the pigment while the B block enables electro-stericstabilization. The polymers having structure III normally have amolecular weight ranging from about 1000 to about 20,000. In anembodiment, the polymer has an acid number ranging from about 130 toabout 200 mg KOH/g polymer. As can be noted in comparing betweenStructure II and III, in the latter, x2 and y3-y5 (per Structure I) arezero (0).

The copolymers having structure IV, include at least two blocks having Aand B groups. Polymers according to Structure IV, have an acrylic estersegment added to the hydrophobic block A. As can be noted in comparingStructure II and IV, in the latter, y3-y5 (per Structure I) are zero(0).

The A block provides for tight encapsulation of the polymer to thepigment while the B block enables electro-steric stabilization. Thepolymers having structure IV normally have a molecular weight rangingfrom about 5000 to about 20,000. In an embodiment, the polymer has anacid number ranging from about 130 to about 200 mg KOH/g polymer.

As can be noted in comparing between Structures I and V, in the lattery1, y2, and y4 (per Structure I) are zero (0).

Polymers made according to Structure V have high glass transitiontemperature. The A block provides total, or at least substantial,hydrophobicity. The B block comprises styrene/maleic anhydridecopolymers (“SMA”) structure which imparts a pen-friendly (ink-jet penor nozzle structure) composition. The B block may have the structures ofSMA-1000 SMA-1440, and SMA-2000. SMA structures are further described inU.S. Pat. No. 6,406,143 B1 issued to Chen et al, the entire content ofwhich is incorporated herein by reference.

Polymers made according to Structure VI include bifunctionalstyrene/acrylate/methacrylate may be used for double chaineddispersants. The double chains can either be the hydrophobic orhydrophilic segments. R′ may be halogen or an alkyl derivative group,provided that when a vinyl benzyl chloride group is used, R′—CH2 is notpresent and the R′CH2CH group becomes CH2.

In an embodiment, polymeric dispersant embodying features of the presentinvention have structure VII:

Polymers made according to Structure VII include random or blockedstructures, depending on whether the small monomers are needed asspacers for the incorporation of reactive surfactant; with S1 and S2representing a surfactant with hydrophobic S1 and hydrophilic S2segments.

In an embodiment, Structure VII may have Structure VIII with methoxyethylene glycol acrylate, SCT-made macromonomers including MAA, AA, orother suitable monomers.

Process

The CRP (Controlled Radical Polymerization) technologies, such as ATRP(atom transfer radical polymerization), NMP (Nitroxide MediatedPolymerization), and RAFT (Reversible Addition Fragmentation ChainTransfer) may be used to synthesize the block copolymers, usable in thestructure polymers as blocks A and B, as well as graft polymer backboneand side chain.

These methods of synthesis have been described in various literature andare practicable by those skilled in the art.

INKS

The aqueous ink jet inks embodying features of the invention employ anaqueous carrier medium (“vehicle”) and a colorant. The colorant may be apigment dispersed according to the present invention. The inks may alsocontain other additives known in the art of ink jet printing.

COLORANT

The colorant may be dispersed according to the present invention. Morethan one pigment may be used in the ink formulation. Preferably, the inkincludes a pigmented colorant suitable for use in inkjet formulations.The following exemplary pigments are useful in the practice of thisinvention; however, this listing is not intended to limit the scope ofthe present invention: pigments available from BASF: Paliogen® Orange,Heliogen® Blue L 6901F, Heliogen® Blue NBD 7010, Heliogen® Blue K 7090,Heliogen® Blue L 7101F, Paliogen® Blue L 6470, Heliogen® Green K 8683,and Heliogen® Green L 9140; Cabot: Monarch® 1400, Monarch® 1300,Monarch® 1100, Monarch® 1000, Monarch® 900, Monarch® 880, Monarch® 800,and Monarch® 700; Cab-O-Jet® series of self-dispersed pigments such asCab-O-Jet 200, 300, (black), Cab-O-Jet 1027R (red), Cab-O-Jet 554B(blue), Cab-O-Jet 270Y (yellow), Cab-O-Jet 250C (cyan), Cab-O-Jet 260M(magenta), PY-74 Yellow; Ciba-Geigy: Chromophtal® Yellow 3G,Chromophtal® Yellow GR, Chromophtal® Yellow 8G, Igrazin® Yellow 5GT,Igralite® Rubine 4BL, Monastral® Magenta, Monastral® Scarlet, Monastral®Violet R, Monastral® Red B, and Monastral® Violet Maroon B; Degussa:Printex U, Printex V, Printex 140U, and Printex 140V; DuPont: Tipure®R-101; Heubach: Dalamar® Yellow YT-858-D and Heucophthal® Blue GXBT-583D; Hoechst: Permanent Yellow GR, Permanent Yellow G, PermanentYellow DHG, Permanent Yellow NCG-71, Permanent Yellow GG, Hansa YellowRA, Hansa Brilliant Yellow 5GX-02, Hansa Yellow-X, Novoperm® Yellow HR,Novoperm® Yellow FGL, Hansa Brilliant Yellow 10GX, Permanent YellowG3R-01, Hostaperm® Yellow H4G, Hostaperm® Yellow H3G, Hostaperm® OrangeGR, Hostaperm® Scarlet GO, and Permanent Rubine F6B; Mobay: Quindo®Magenta, Indofast® Brilliant Scarlet, Quindo® Red R6700, Quindo® RedR6713, and Indofast® Violet; Sun Chem: L74-1357 Yellow, L75-1331 Yellow,and L75-2577 Yellow, Pigment Red PR122 Red; Clariant Hostajet® PT and STseries: Hostajet Yellow 4G-PT VP 2669, Hostajet Magenta E-PT VP 2690,Hostajet Cyan BG-PT VP 2689, Hostajet Black O-PT VP 2676; HostajetYellow 4G-ST VP 2745, Hostajet Magenta E-ST, Hostajet Cyan BG-ST VP2778. Other exemplary pigments include anthraquinone red (PR177),pyrrole red (PR254), anthraqinone scarlet (PR168), quinacridone magenta(PR202), phthalocyanine green (PG36), chlorinated copper phthalocyaninegreen (PG7), dioxazine violet (PV23), and beta quinacridone violet(PV19); available from Companies such as Sun Chemical and Clariant.

As used herein, the term “pigment” refers to a colorant that isinsoluble in the aqueous vehicle, and includes disperse dyes andself-dispersed pigments, dispersed using dispersions embodying featuresof the present invention. A wide variety of organic and inorganicpigments, alone or in combination, may be selected to make the ink,examples of which are disclosed in U.S. Pat. No. 5,085,698. Thedispersed pigment particles are sufficiently small to permit free flowof the ink through the inkjet printing device, especially at theejecting nozzles that usually have a diameter ranging from 10 micron to50 micron. The particle size also has an influence on the pigmentdispersion stability, which is critical throughout the life of the ink.Brownian motion of minute particles can help prevent the particles fromflocculating. It is also desirable to use small particles for maximumcolor strength and gloss. The range of useful particle size isapproximately 0.005 micron to 15 micron. Preferably, the pigmentparticle size should range from 0.005 to 5 micron and, next preferably,from 0.010 to 1 micron, and most preferably, from about 0.010 to 0.3micron.

The colorant, when present in the ink, may be added to the ink in anamount generally ranging from about 0.1 to about 15%, from about 0.2 toabout 10%, or from about 0.5 to about 5%, by weight, based on the totalweight of the ink.

Aqueous Vehicle

The vehicle for the ink may comprise an aqueous-based vehicle thatincludes water or a mixture of water and at least one water-solubleorganic solvent. Selection of a suitable mixture depends on requirementsof the specific application, such as desired surface tension andviscosity, the selected colorant, drying time of the liquid, and thetype of substrate onto which the liquid will be printed. Representativewater-soluble organic solvents that may be selected are disclosed inU.S. Pat. No. 5,085,698, the full disclosure of which is incorporatedherein by reference.

More specifically, the water-soluble organic solvent may include, but isnot limited to, aliphatic alcohols, aromatic alcohols, diols, glycolethers, poly(glycol) ethers, caprolactams, formamides, acetamides, andlong chain alcohols, or any mixtures thereof. Examples of organicsolvents employed in the practice of this invention include, but are notlimited to, primary alcohols of 30 carbons or less, primary aromaticalcohols of 30 carbons or less, secondary aliphatic alcohols of 30carbons or less, secondary aliphatic alcohols of 30 carbons or less,1,3-alkyldiols of 30 carbons or less, alkyltriols of 30 carbons or less,1,3-alcohols of 30 carbons or less, ethylene glycol alkyl ethers,propylene glycol alkyl ethers, poly(ethylene glycol) alkyl ethers,higher homologs of poly(ethylene glycol) alkyl ethers, poly(propyleneglycol) alkyl ethers, higher homologs of poly(propylene glycol) alkylethers, N-alkyl caprolactams, unsubstituted caprolactams, substitutedformamides, unsubstituted formamides, substituted acetamides, andunsubstituted acetamides. Specific organic solvents that are preferablyemployed in the practice of this invention include, but are not limitedto, N-methylpyrrolidone, 1,5-pentanediol, 2-pyrrolidone,1-(2-hydroxyethyl)-2-pyrrolidone, diethylene glycol,1,3-(2-methyl)-propanediol, 1,3,5-(2-methyl)-pentanetriol,tetramethylene sulfone, 3-methyl-1-butanol, glycerol, 3-pyridylcarbinol,pentaerythritol, 1,6-hexanediol, 1,2-alkyldiols, and mixtures thereof.For instance, the water-soluble organic solvent in the ink vehicle mayinclude a mixture of diol, a polyglycol ether, and a glycol ether.

In the case of a mixture of water and at least one water-solublesolvent, the aqueous carrier medium usually comprises from about 30% toabout 95% water. Generally the compositions may comprise from about 60%to about 95% water, based on the total weight of the aqueous carriermedium. The water-soluble organic solvent(s), independently, maygenerally be added to the liquid (e.g., ink or performance enhancingliquid) in an amount generally ranging from about 1 wt % to about 50 wt% of the total weight of the liquid formulation; from about 2 to about45 wt %, or from about 5 to about 35 wt %.

Additional Components

Consistent with the invention, various types of additives, may beemployed in the inks (or the performance optimizing liquid) to optimizethe properties of the ink compositions for specific applications. Theremainder of the ink composition is mostly water; however, otherindependently selected components including surfactants, humectants,anti-kogation additives, anticorrosive additives, polymers,preservatives, biocides that inhibit growth of microorganisms such asthe preservative PROXEL™ GXL (available from Avecia Incorporated);chelating agents (or sequestering agents) such as EDTA that eliminatedeleterious effects of heavy metal impurities; buffers; and viscositymodifiers, may be added to improve various properties of the inkcomposition.

Buffers may be used to maintain the inkjet ink at a desired pH. Thebuffer may be an organic-based biological buffer or an inorganic buffer.The buffers employed are chosen to sufficiently maintain the pH in thedesired range. Examples of buffers include Trizma Base, available fromSigma-Aldrich Corp. (Milwaukee, Wis.); 4-morpholine ethane sulfonic acid(“MES”); 4-morpholinepropanesulfonic acid (“MOPS”); andbeta-hydroxy-4-morpholinepropane-sulfonic acid (“MOPSO”).

EXAMPLES

The general composition of exemplary polymers made for use asdispersants embodying features of the invention are shown in TABLES Ithrough V, along with exemplary ranges of amount of ingredients makingup each component.

In the present application including all the tables, the followingapplies:

The following abbreviations refer to: AA is acrylic acid; MAA ismethacrylic acid; ETEGMA is ethyltriethyleneglycolmethacrylate; Sty isstyrene; BMA is butylmethacrylate; BzMA is benzylmethacrylate; IBOMA isisobornylmethacrylate.

The molecular weight is a calculated molecular weight based on thenumber of units as shown in TABLES I-V. Molecular weights as measured byGPC would be relative to the Styrene standards used to calibrate thesystem.

Random denotes random copolymers formed using standard radical reactiontechniques; SCT denotes Random copolymers formed using Co-SCT complex,resulting in macromonomers with terminal olefin groups; Graft denotesRandom copolymers formed using small molecule monomers andmacromonomers; Block denotes Structured copolymers formed using specialreaction conditions, Bold underlined text in the body of TABLES denotesblock A of the AB polymer; Gradient denotes Copolymers where thetransition from one monomer type to another is gradual instead ofsudden.

The numbers in the rows across from each monomer type indicate theaverage unit of each monomer type.

Examples 7-10 refer to exemplary hydrophilic macromonomers. It isfurther understood that styrene (Sty) may be replaced by BzMA/IBOMAmixtures. ETEGMA may also be replaced by hydrophilic monomers such asHEMA (hydroxyethyl methacrylate). Examples 11-14 are exemplaryhydrophobic macromonomers. In all examples methacrylates my be replacedby acrylates, provided the backbone Tg is maintained. In all examplesadhesion promoting monomers, such as those in U.S. Pat. No. 6,037,390may be substituted for ETEGMA.

Block polymers according to Examples 15-32 may be made usingmacromonomers 7-14 which may be made using the monomer types describedin the following tables.

By way of example, the following is a description for preparation ofdispersant/s embodying features of the present invention.

Preparation of poly(t-BA/t-BMA)—Copper(I) bromide (8.66 g) was taken ina flask and saturated with nitrogen. Acetone (120 ml) was added to theabove, and was followed by adding Pentamethyl diethylene triamine‘PMDETA’ (13.3 ml). After a period of time, a mixture of t-butylacrylate (90.6 g) and t-butyl methacrylate (109.4 g) was added. This newmixture was cooled to 5° C. Thereafter, the initiator methylbromopropionate (37 ml) was added to the cooled mixture. Temperature ofthe mixture was maintained at 5° C. for approximately one hour. Themixture was stirred at room temperature for approximately forty one (41)hours. An NMR spectrum of the sample after one (1) hour indicated apolymerization of about 95%. The mixture was then heated to 75° C. forabout one (1) hour and cooled. Acetone (80 g) was added to dilute themixture. The mixture was filtered through neutral alumina column. Thesolvent was removed and the title polymer with bromo end group wasobtained. The yield of the whole process was approximately 95%.

Preparation of poly(AA/MAA-block-styrene)-.A solution of macro-initiatorfrom Example 1 (41.16 g) in styrene (112.95 g) and toluene (40 ml) wasprepared. Copper (I) chloride (2.53 g) was taken in a 500 ml flask andsaturated with nitrogen. Toluene (40 ml) was added followed by PMDETA(3.9 ml). The color of mixture turned dark green indicative of theformation of copper complex. The macro-initiator containing styrenesolution was added to the copper complex solution. The combined solutionwas heated to about 95° C. for about 6 hour. The heating was stopped andsolution was cooled to room temperature. The cooled solution was dilutedwith hexane and filtered through neutral alumina column to remove thecopper complex. The solvents and the excess styrene monomer were removedunder reduced pressure. The polymer obtained was dissolved indichloromethane (200 ml) and mixed with trifluoroacetic acid (180 g).The mixture was stirred at room temperature overnight to hydrolyze thet-butyl group as confirmed by the disappearance of t-butyl group at 1.4ppm in a proton NMR spectrum. All or almost all of the volatilematerials were removed under reduced pressure and the polymer obtainedwas dissolved again in tetrahydrofuran (250 ml) and precipitated in coldhexane (1.4 L). The precipitated polymer was collected and dried invacuum at 70° C. for about 48 hours to obtain the polymer with blocks ofstyrene and a mixture of acrylic and methacrylic acids.

TABLE I Example ID Comp 1 Comp 2 Ex 1 Ex 2 Ex 3 Ex 4 Ex 5 Ex 6 PolymerType Random Random Random Random Random Random Random Random Mw 800010000 10251 12813 11435 14294 14989 18737 AA 11 14 11 14 11 14 11 14 MAA12 15 12 15 12 15 12 15 ETEGMA Sty 59 74 BMA 59 74 BzMA 59 74 IBOMA 5974

TABLE II Example ID Ex 7 Ex 8 Ex 9 Ex 10 Ex 11 Ex 12 Ex 13 Ex 14 PolymerType SCT SCT SCT SCT SCT SCT SCT SCT Mw 2034 4164 4068 8328 2600 52004608 9216 AA 3 3 6 6 MAA 3 3 6 6 ETEGMA 15 30 Sty 15 30 25 50 BMA BzMA12 24 IBOMA 12 24

TABLE III Example ID Ex 15 Ex 16 Ex 17 Ex 18 Ex 19 Ex 20 Polymer TypeGraft Graft Graft Graft Graft Graft Mw 13336 21856 42944 77024 1759659984 AA MAA ETEGMA Sty 50 50 100 100 50 100 BMA BzMA IBOMA Ex 7 4 2 Ex8 4 2 Ex 9 8 4 Ex 10 8 4 Ex 11 Ex 12 Ex 13 Ex 14

TABLE IV Example ID Ex 21 Ex 22 Ex 23 Ex 24 Ex 25 Ex 26 Polymer BlockBlock Block Block Block Block Type Mw 13336 21856 42944 77024 18760  32320   AA 20 40 MAA 20 40 ETEGMA Sty    50    50   100   100 50 50 BMABzMA IBOMA Ex 7   4 Ex 8   4 Ex 9   8 Ex 10   8 Ex 11   4 Ex 12   4 Ex13 Ex 14

TABLE V Example ID Ex 27 Ex 28 Ex 29 Ex 30 Ex 31 Ex 32 Polymer TypeBlock Block Block Block Block Block Mw 50424   90448   26896   48976  82968   157072   AA 20 40 20 40 20 40 MAA 20 40 20 40 20 40 ETEGMA Sty100   100   50 50 100   100   BMA BzMA IBOMA Ex 7  4 Ex 8  4 Ex 9  8 Ex10  8 Ex 11   4 Ex 12   4 Ex 13   8   8 Ex 14   8   8

Acid numbers were measured for select polymers as described below inorder to asses the number of acid sites on the polymer, the results ofwhich are shown in TABLE VI. An exemplary method for measuring the acidnumber included weighing about 100 milli-grams (mg) of the polymer anddissolving in a 50 milliliters (ml) of THF and 25 ml of IPA in atitration beaker mounted on a Mettler DL77 titrator. Ten (10) ml ofwater was slowly added to the solution while mixing. For sample P3, anadditional 25 ml (total of 75 ml) was used to keep the polymer dissolvedprior to titration. A titrant of 0.500N KOH was added to the polymersolution using a Mettler SC115 combination pH electrode and buret tip (1ml buret). The solution was titrated in the dynamic equilibrium mode tothe end of the titration.

TABLE VI Average Molecular Meq of mg of weight KOH/g KOH/g Sample IDPolymer Type (Mw) polymer polymer P1 Benzylmethacrylate- 6.3 × 10³ 0.9251 P2 block-Acrylic 6.0 × 10³ 1.30 73 P3 Acid/Methacrylic Acid 2.3 × 10³1.43 80 P4 Styrene-block-Acrylic 9.2 × 10³ 1.55 87 P5 Acid/MethacrylicAcid 2.2 × 10³ 2.13 119

While particular forms of the invention have been illustrated anddescribed herein, it will be apparent that various modifications andimprovements can be made to the invention. Moreover, individual featuresof embodiments of the invention may be shown in some drawings and not inothers, but those skilled in the art will recognize that individualfeatures of one embodiment of the invention can be combined with any orall the features of another embodiment. Accordingly, it is not intendedthat the invention be limited to the specific embodiments illustrated.It is intended that this invention to be defined by the scope of theappended claims as broadly as the prior art will permit.

Terms such a “element,” “member,” “component,” “device,” “section,”“portion,” “step,” “means,” and words of similar import, when usedherein shall not be construed as invoking the provisions of 35 U.S.C.§112(6) unless the following claims expressly use the term “means”followed by a particular function without specific structure or the term“step” followed by a particular function without specific action.Accordingly, it is not intended that the invention be limited, except asby the appended claims. All patents and patent applications referred toherein are hereby incorporated by reference in their entirety.

1. A pigment dispersion, comprising: a. at least one dispersed pigment;an aqueous carrier; and b. at least one block copolymer dispersantconsisting of Structure I, which has a copolymeric hydrophobic block (A)and a different copolymeric hydrophilic block (B);

Wherein C is

D is

E is

F is

G is

x1 and x2 are independently selected to be greater than zero (0) andhydrophobic block (A) exhibits a Tg of from about 65 to about 140degrees Celsius (° C.); y1 through y5 are independently selected to beequal to or greater than zero (0), but at least two of y1 through y5 aregreater than 0, including at least one of y1, y2, and y5; R1 is H orCH3; R2 is alkyl, or aryl group wherein the numbers of carbon atomsranges from 0 to about 20, including benzyl, butyl, or ester group; andR3 is H, an alkyl group of from 1 to about 15 carbon atoms, an arylgroup of from about 6 to about 18 carbon atoms; arylalkyl;polydimethylsiloxane; polyethylene glycol chain; or a polypropyleneglycol chain wherein monomer D in the hydrophobic block A is selectedfrom the group consisting of benzylmethacrylate, isobornylmethacrylate,and combinations thereof.
 2. A pigment dispersion according to claim 1,wherein y1 through y4 are greater than 0 and y5 is
 0. 3. A pigmentdispersion according to claim 1, comprising both benzylmethacrylate andisobornylmethacrylate as monomer D in the hydrophobic block (A).
 4. Apigment dispersion according to claim 1, wherein y1 and y2 are greaterthan 0 and y3-y5 are
 0. 5. A pigment dispersion according to claim 1,wherein y3 and y5 are greater than 0 and y1, y2, and y4 are
 0. 6. Thepigment dispersion of claim 1, wherein y5 is zero; y1, y2, and y4 aregreater than 0; monomer D in the hydrophobic block A is selected fromthe group consisting of benzylmethacrylate, isobornylmethacrylate, andcombinations thereof; and monomer D in the hydrophilic block B isselected from the group consisting ofethyltriethyleneglycolmethacrylate, butylmethacrylate,hydroxyethylmethacrylate, and combinations thereof.
 7. The pigmentdispersion of claim 1, wherein y4 is greater than 0 and monomer D in thehydrophilic block (B) is selected from the group consisting ofethyltriethyleneglycolmethacrylate, hydroxyethylmethacrylate, andcombinations thereof.
 8. The pigment dispersion of claim 1 wherein theTg of the A block ranges from about 70 to about 120° C.
 9. The pigmentdispersion of claim 1, wherein the pigment dispersion is formulated intoan inkjet ink.
 10. The pigment dispersion of claim 3, wherein the Tg ofthe A block ranges from about 70 to about 120° C.
 11. The pigmentdispersion of claim 3, wherein the dispersion has an acid number rangingfrom about 130 to about 200 mg KOH/g polymer.
 12. A pigment dispersionaccording to claim 4, wherein the dispersant having Structure I has aweight average molecular weight ranging from about 5000 to about 20,000.13. The pigment dispersion of claim 4, wherein the hydrophobic A blockincludes an acrylic ester group.
 14. A pigment dispersion, comprising:a. at least one dispersed pigment; an aqueous carrier; b. at least oneblock copolymer dispersant consisting of Structure I, which has acopolymeric hydrophobic block (A) and a different copolymerichydrophilic block (B) and having a weight average molecular weightranging from about 5000 to about 20,000;

Wherein C is

D is

E is

F is

G is

x1 and x2 are independently selected to be greater than zero (0) andhydrophobic block (A) exhibits a Tg of from about 65 to about 140degrees Celsius (° C.); y1 and y2 are greater than 0 and y3-y5 are 0; R1is H or CH3; and R2 is alkyl, or aryl group wherein the numbers ofcarbon atoms ranges from 0 to about 20, including benzyl, butyl, orester group; and c. the dispersion having an acid number ranging fromabout 130 to about 200 mg KOH/g polymer wherein monomer D in thehydrophobic block A is selected from the group consisting ofbenzylmethacrylate, isobornylmethacrylate, and combinations thereof. 15.The pigment dispersion of claim 14, wherein the hydrophobic A blockincludes an acrylic ester group.
 16. The pigment dispersion of claim 14,wherein the pigment dispersion is formulated into an inkjet ink.
 17. Apigment dispersion, comprising: a. at least one dispersed pigment; anaqueous carrier; and b. at least one block copolymer dispersantconsisting of Structure I, which has a copolymeric hydrophobic block (A)and a different copolymeric hydrophilic block (B);

Wherein C is

D is

E is

F is

G is

x1 and x2 are independently selected to be greater than zero (0) andhydrophobic block (A) exhibits a Tg of from about 70 to about 120degrees Celsius (° C.); y3 and y5 are greater than 0 and y1, y2, and y4are 0; R1 is H or CH3; R2 is alkyl, or aryl group wherein the numbers ofcarbon atoms ranges from 0 to about 20, including benzyl, butyl, orester group; and R3 is H, an alkyl group of from 1 to about 15 carbonatoms, an aryl group of from about 6 to about 18 carbon atoms;arylalkyl; polydimethylsiloxane; polyethylene glycol chain; or apolypropylene glycol chain wherein monomer D in the hydrophobic block Ais selected from the group consisting of benzylmethacrylate,isobornylmethacrylate, and combinations thereof.
 18. The pigmentdispersion of claim 17, wherein the pigment dispersion is formulatedinto an inkjet ink.